Semi-submersible work platform

ABSTRACT

A semi-submersible work platform comprising a deck with oppositely disposed projections extending outwardly. Twin hull members, adapted to float said deck, are transversely spaced and braced apart, and mount upright columns that are spaced and secured around the perimeter of the working deck. The hulls are rectangular in cross-section for damping motion and pointed at both ends for double-ended use in moving. Motion damping fins are mounted on said hulls and extend outwardly and parallel to the deck projections and are vertically aligned therewith. Hydrodynamically shaped stability columns are turnably mounted between each of said deck projections and associated damping fins for the triple use of reducing drag on the work platform, steering the rig while underway, and partially in controlling draft and trim thereof. Propulsion may be added to each of the stability columns at their respective lower ends.

United States Patent 1191 'Pazos 1111 3,763,809 Oct. 9, 1973 SEMISUBMERSIBLE WORK PLATFORM [76] Inventor: HectorVV. Pazos, 2728 ValentineCt., New Orleans, La. 70114 [22] Filed: May 25, 1972 [2i] Appl. No.:263,012

Glosten l 14/.5 D

Primary Examiner-Trygve M. Blix Assistant Examiner-Stuart M. GoldsteinAttorney-James B. Lake, Jr.

[5 7 ABSTRACT A semi-submersible work platform comprising a deck withoppositely disposed projections extending outwardly. Twin hull members,adapted to float said deck, are transversely spaced and braced apart,and mount upright columns that are spaced and secured around theperimeter of the working deck. The hulls are rectangular incross-section for damping motion and pointed at both ends fordouble-ended use in moving. Motion damping fins are mounted on saidhulls and extend outwardly and parallel to the deck projections and arevertically aligned therewith. Hydrodynamically shaped stability columnsare tumably mounted between each of said deck projections and associateddamping fins for the triple use of reducing drag on the work platform,steering the rig while underway, and partially in controlling draft andtrim thereof. Propulsion may be added to each of the stability columnsat their respective lower ends.

6 Claims, 6 Drawing Figures 1 SEMI-SUBMERSIBLE WORK PLATFORM Theinvention relates generally to semi-submersible work platforms and moreparticularly to platforms that are adapted to floating and grounded use.

Heretofore semi-submersible work platforms have taught a boat-shapedmember fixed to a base of each of a plurality of supporting columns.Where columns are used for stability purposes, these functions areincdrporated in said supporting fixed columns.

It is an object of the invention to provide a semisubmersible workplatform having separate support and stability columns, the later beingmounted outboard of the former and tear-drop shape in cross section fortheir submersible extent.

Another object of the invention is to provide turnable stability columnsthat are usable for steering and reducing dragwhen immersed inrelatively moving water.

Another object of the invention is to provide dual purpose motiondamping and structure strengthening means for said work platform.

-' Another object of the invention is to provide a semisubmersible workplatform in which self-propulsion can be optionally installed.

Other objects and a fuller knowledge of the invention may be had byreferring to the following specification, claims and drawings in which:

FIG. 1 is a side elevation of the invention with optional propulsionunits installed,

FIG. 2 is a partial enlarged plan view of a deck projection,

FIG. 3 an enlarged vertical cross-section of a part of FIG. 1 showingturnable mounting of a stability column,

FIG. 4 is an enlarged cross section of a part of FIG.

FIG. 5 is a cross-sectional view taken along section ity columns 22 aresupported for rotation or turning between fins l8 and diagonalprojections 20. Hull members 16 are held together together in catamaranconfiguration with cross bracing 26, and joined to said deck by thesupport and stability columns. Propulsion units 28 can be mounted in thelower ends of stability columns 22 as shown in FIG. 1, the externalparts 30 of said units being secured to said stability columns by pins32 and 34.

More particularly and referring additionally to FIGS. 24 and 6, astability column 22 is hydrodynamically shaped in cross-section (FIG. 5)and is round with reduced radii for the portions at it top 36 and bottom38 for economy of mounting for turning (FIGS. 3 and 6). Ball bearings 40are'mounted in a ball race 41 bolted between a projection 20 and top 36.A hold down'ring 42 closes the race which turnably supports top ofcolumn 22. The reduced bottom 38 fits into a hole defined in associatedfin 18. A bushing 46 turnably supports bottom 38 in said hole. Thehollow columns houses optional propulsion machinery 48 and ventilationducts 50. Access to machinery is through the stability columns also. Amotor 52 mounted adjacent to top 36 drives a spur gear 54 that mesheswith toothed flange 56 secured to top 36 of each stability column 22.The arrangement is illustrated in FIGS. 2 and 3.

The work platform 12 can become self propelled with the mounting ofpropulsion apparatus in the lower end of each stability column 22 andsteered by turning the hydrodynamically shaped stability columns 22.Propellers 58 can be mounted in Kort nozzles 60 as shown in FIG. 5 toimprove directional propulsion and assist in steering.

Work platform 12 travels as shown in FIG. 1 at lowestwaterline.Flotation tanks (not shown) in hull members l6 and, if desired, instability columns 22, can be flooded to sink the platform to any desireddepth, or occasionally to the sea bottom, as limited by the upperwaterline. In either case stability columns stabilize work platform 12and when turned for blunt edges to face into any relative water flow toreduce the effects of such flow on the platform to a minimum. Pumpingmeans (not shown) can be provided on or off the platform for evacuatingsaid flotation tanks prior to moving the platform.

I claim:

1. A semi-submersible work platform, having a hull structure, a workdeck, and supporting columns fixing said work deck to the hull structurein vertical spaced relationship, comprising: parallel projectionssymmetrically fixed around outer perimeters of said hull structure andwork deck respectively, said projections extending outboard of saidsupport columns and being arranged in pairs, the projections of eachpair arranged in vertically aligned and spaced relationship; upper andlower mounting means, vertically aligned and spaced, defined by eachsaid pair of projections for turnably engaging oppositely disposedcylindrical ends of stability columns;said stability columns, havingrespectively oppositely disposed ends and vertical axes, adaptedrespectively to being mounted between each of said pairs of projectionsby said respective upper and lower mounting means for turning about eachof their said vertical axes, said stability columns being hollow andhydrodynamically shaped in cross-section for a portion intermediatetheir respectively oppositely disposed ends, whereby said stabilitycolumns stabilizes said semi-submersible work platform, can be turnedabout their respective vertical axes to steer when underway and toreduce drag of columns when stationary in moving water.

2. A semi-submersible platform as described in claim 1 wherein saidhydrodynamically shaped stability columns are tear shaped incross-section.

. 3. A semi-submersible work platform as described in claim 1 whereinsaid upper and lower mounting means comprises respectively ball racesand bushings.

4. A semi-submersible work platform as described in claim 1 wherein theends of said stability columns are cylindrical for turnably engaging insaid upper and lower mounting means, and are smaller in diameter thanthe hydrodynamically shaped portion for reducing the sizes of saidmounting means.

5. A semi-submersible work platform as described in claim 1 wherein saidhollow stability columns defines space for mounting propulsion machineryadjacent each said lower mounting means.

6. A semi-submersible work platform as described in claim 1 wherein saidhull structure defines a catamaran l 4' i i l

1. A semi-submersible work platform, having a hull structure, a workdeck, and supporting columns fixing said work deck to the hull structurein vertical spaced relationship, comprising: parallel projectionssymmetrically fixed around outer perimeters of said hull structure andwork deck respectively, said projections extending outboard of saidsupport columns and being arranged in pairs, the projections of eachpair arranged in vertically aligned and spaced relationship; upper andlower mounting means, vertically aligned and spaced, defined by eachsaid pair of projections for turnably engaging oppositely disposedcylindrical ends of stability columns; said stability columns, havingrespectively oppositely disposed ends and vertical axes, adaptedrespectively to being mounted between each of said pairs of projectionsby said respective upper and lower mounting means for turning about eachof their said vertical axes, said stability columns being hollow andhydrodynamically shaped in cross-section for a portion intermediatetheir respectively oppositely disposed ends, whereby said stabilitycolumns stabilizes said semi-submersible work platform, can be turnedabout their respective vertical axes to steer when underway and toreduce drag of columns when stationary in moving water.
 2. Asemi-submersible platform as described in claim 1 wherein saidhydrodynamically shaped stability columns are tear shaped incross-section.
 3. A semi-submersible work platform as described in claim1 wherein said upper and lower mounting means comprises respectivelyball races and bushings.
 4. A semi-submersible work platform asdescribed in claim 1 wherein the ends of said stability columns arecylindrical for turnably engaging in said upper and lower mountingmeans, and are smaller in diameter than the hydrodynamically shapedportion for reducing the sizes of said mounting means.
 5. Asemi-submersible work platform as described in claim 1 wherein saidhollow stability columns defines space for mounting propulsion machineryadjacent each said lower mounting means.
 6. A semi-submerSible workplatform as described in claim 1 wherein said hull structure defines acatamaran.